This invention relates generally to transducer devices for use in monitoring the position of a mechanical device such as a valve or the like at a remote location. More particularly, this invention relates to a fiber optic transducer designed for improved and simplified remote monitoring of a mechanical device.
Remote position monitoring of mechanical devices is required or desirable in many different industrial applications. For example, in many petroleum and/or chemical processing facilities, it is frequently desirable to monitor the on-off state of various flow control valves to check proper operation of the facility. This monitoring function is preferably performed from a centralized, safe monitoring position remote from the actual valves, thereby permitting simultaneous monitoring of the facility or system by a single operator. Moreover, in some types of facilities, the nature of the materials being processed makes it necessary to avoid use of traditional transducer devices of the type requiring electrical wiring or electrical signals at the site of the valve or other mechanical devices being monitored.
In the past, some transducers have been developed utilizing an optical fiber as the primary component to indicate the position or change in position of a mechanical device. More specifically, it has been recognized that a portion of the light transmitted along an optical fiber is lost at the site of a bend in the fiber, and further that the magnitude of light loss increases directly with the magnitude of the bend. Accordingly, transducers have been constructed to bend optical fibers in response to various mechanical movements, with appropriate remote detection of transmission attenuation providing an indication of the mechanical movement. However, in such prior optical fiber transducers, accurate correlation and calibration between the light loss and the precise mechanical movement, particularly for devices such as rotary valves and the like, has not been satisfactorily obtained.
There exists, therefore, a significant need for an improved optical fiber transducer for use in providing an accurate and easily calibrated indication of mechanical position which can be monitored from a remote site. The present invention fulfills these needs and provides further related advantages.